A Fast Rendering Method for a Scene with Participating Media of Anisotropic Scattering Property

Stony Brook,New York, USA, June22-24 2005This paper presents an efficient technique for global illumination rendering of a scene with participating media. The rendering handling participating media is performed by ray marching method, which requires sampling along each view direction. The step size of the ray marching must be taken short to generate a high quality image and thus leads to very long computational time. One possible method to improve the computational cost is to exploit importance sampling.In this paper, we propose a method to determine the step size based on the importance sampling technique. For efficient sampling, the probability density function which is ”close” to the radiance distribution is required. In our method, 3D space is divided into a set of uniform grids.The radiance distribution is approximated using the grid structure. To deal with the participating media which has anisotropic scattering property, we use spherical harmonics to represent directional dependence of radiance distribution.Using this grid-based representation, fast calculation of good approximation of desirable probability density is made possible. Using this probability, high quality image can be rendered with fewer numberArticleComputer Graphics International 2005 (CGI2005):227-233 2005conference pape

INFLUENCE OF ALTERING BREATHING TECHNIQUES ON PASSIVE DRAG: A PRELIMINARY REPORT

The purpose of this study was to examine if passive drag could be altered by adopting different breathing techniques; chest breathing technique and abdominal breathing technique. Six male subjects participated in this study. Each Subject was towed at a constant towing force in the glide position with inflating their chest or abdomen. The steady-state velocity was measured and the drag coefficients was calculated for each breathing technique. Results showed that the towing velocity was significantly greater with abdominal breathing technique than with chest breathing technique (

The competitiveness of domestic rice production in East Africa: A domestic resource cost approach in Uganda

The rapid increase of rice imports in sub-Saharan Africa under the unstable situation in the world rice market during the 2000s has made it an important policy target for the countries in the region to increase self-sufficiency in rice in order to enhance food security. Whether domestic rice production can be competitive with imported rice is a serious question in East African countries that lie close, just across the Arabian Sea, to major rice exporting countries in South Asia. This study investigates the international competitiveness of domestic rice production in Uganda in terms of the domestic resource cost ratio. The results show that rainfed rice cultivation, which accounts for 95% of domestic rice production, does not have a comparative advantage with respect to rice imported from Pakistan, the largest supplier of imported rice to Uganda. However, the degree of non-competitiveness is not serious, and a high possibility exists for Uganda’s rainfed rice cultivation to become internationally competitive by improving yield levels by applying more modern inputs and enhancing labour productivity. Irrigated rice cultivation, though very limited in area, is competitive even under the present input-output structure when the cost of irrigation infrastructure is treated as a sunk cost. If the cost of installing irrigation infrastructure and its operation and maintenance is taken into account, the types of irrigation development that are economically feasible are not large-scale irrigation projects, but are small- and microscale projects for lowland rice cultivation and rain-water harvesting for upland rice cultivation

Green fluorescence from cnidarian hosts attracts symbiotic algae

Reef-building corals thrive in nutrient-poor marine environments because of an obligate symbiosis with photosynthetic dinoflagel-lates of the genus Symbiodinium. Symbiosis is established in most corals through the uptake of Symbiodinium from the environment. Corals are sessile for most of their life history, whereas free-living Symbiodinium are motile; hence, a mechanism to attract Symbiodinium would greatly increase the probability of encounter between host and symbiont. Here, we examined whether corals can attract free-living motile Symbiodinium by their green fluorescence, emitted by the excitation of endogenous GFP by purple-blue light. We found that Symbiodinium have positive and negative phototaxis toward weak green and strong purpleblue light, respectively. Under light conditions that cause corals to emit green fluorescence, (e.g., strong blue light), Symbiodinium were attracted toward live coral fragments. Symbiodinium were also attracted toward an artificial green fluorescence dye with similar excitation and emission spectra to coral-GFP. In the field, more Symbiodinium were found in traps painted with a green fluorescence dye than in controls. Our results revealed a biological signaling mechanism between the coral host and its potential symbionts

Auricular Acupuncture at the “Shenmen” and “Point Zero” Points Induced Parasympathetic Activation

Purpose. Since auricular acupuncture is a diagnostic and treatment system based on normalizing the body’s dysfunction, auricular acupuncture has been applied for pain relief, relaxation, and so on. These techniques would modulate the autonomic nerve system, thereby inducing the above-mentioned effects. The aim was to see the effect of auricular acupuncture applied to the “Shenmen” and “Point Zero” points on the postoperative heart rate variability (HRV). Methods. Twenty-six patients who underwent hemicolectomy under general anesthesia were randomized into the control or the acupuncture group. After the operation and before emergence, the acupuncture group received auricular acupuncture. An electrocardiographic unit was placed for recording the autonomic nervous activities. Results. The low frequency (LF)/high frequency (HF) ratio of HRV increased () in the control, but the ratio in the acupuncture did not change. There were significant differences between the ratios of the two groups at 3 : 00, 4 : 00, and 5 : 00. HF of the acupuncture group tended to be higher. HFs of the acupuncture group were significantly higher than those of the control group at 3 : 00, 4 : 00, and 5 : 00. Conclusion. Auricular acupuncture kept the LF/HF ratio at lower levels and HF at higher levels during postoperative period in the patients who had undergone hemicolectomy

Local Gene Delivery System by Bubble Liposomes and Ultrasound Exposure into Joint Synovium

Recently, we have developed novel polyethylene glycol modified liposomes (bubble liposomes; BL) entrapping an ultrasound (US) imaging gas, which can work as a gene delivery tool with US exposure. In this study, we investigated the usefulness of US-mediated gene transfer systems with BL into synoviocytes in vitro and joint synovium in vivo. Highly efficient gene transfer could be achieved in the cultured primary synoviocytes transfected with the combination of BL and US exposure, compared to treatment with plasmid DNA (pDNA) alone, pDNA plus BL, or pDNA plus US. When BL was injected into the knee joints of mice, and US exposure was applied transcutaneously to the injection site, highly efficient gene expression could be observed in the knee joint transfected with the combination of BL and US exposure, compared to treatment with pDNA alone, pDNA plus BL, or pDNA plus US. The localized and prolonged gene expression was also shown by an in vivo luciferase imaging system. Thus, this local gene delivery system into joint synovium using the combination of BL and US exposure may be an effective means for gene therapy in joint disorders